A test has been developed to measure temporal sensitivity losses in glaucoma and ocular hypertension. This test shows significant deficits at high temporal frequencies in 95% of eyes with elevated intraocular pressure, in patients exhibiting glaucoma with visual field losses in the other eye. The purposes of the present proposal are: I. to evaluate and improve the temporal sensitivity test for this particular clinical application. This will involve studies of the reliability, effects of age and effects of optical deficits in the performance of the test. The optimal luminance level for detecting glaucomatous losses will be determined. II. to study its efficacy in the diagnosis of glaucoma and prognosis of the development of the disease. This will involve a prospective study of the predictive accuracy of temporal sensitivity losses in different classes of ocular hypertension, and cross-sectional correlations with clinical indices of the severity of glaucoma. Comparisons will be made with the temportal effects of other retinal pathologies. III. to use it as a tool in investigating the etiology of glaucoma. Changes in temporal sensitivity losses will be determined with various methods of manipulating intraocular pressure. The interactions of sensitivity loss with luminance will be used to identify the type of retinal mechanism that is affected early in the course of the disease.